Stereotactic High Dose Fraction Radiation Therapy of Extracranial Tumors Using An Accelerator: Clinical experience of the first thirty-one patients

Abstract

EXTRACRANIAL TUMORS USING AN ACCELERATORClinical experience of the first thirty-one patients HENRIC BLOMGREN, INGMAR LAX, INGEMAR NASLUND and RUT SVANSTROMA stereotactic body frame with a fixation device has been developed for stereotactic radiation therapy of extracranial targets, a precision localization and positioning system in analogy with the stereotactic head frames used for intracranial targets. Results of the first 42 treated tumors in 31 patients are presented. Most of the patients had solitary tumors in liver, lung or retroperitoneal space. Clinical target volumes ranged from 2 to 622 cm3 (mean 78 cm3) and minimum doses to the planning target volumes (PTV) of 7.7-30 Gy/fraction (mean 14.2 Gy) were given on 1-4 occasions to a total minimum dose to the PTVs of 7.7-45 Gy (mean 30.2 Gy) to the periphery of the PTV and total mean doses to the PTVs of 8-66 Gy (mean 41 Gy). The central part of the tumor was usually given about 50% higher dose compared to that of the periphery of the PTV by a planned inhomogeneous dose distribution. Some of the patients received stereotactic radiation therapy concomitantly to more than one target, in others new metastases were also treated which appeared during the follow-up period. We observed a local rate of no progressive disease of 80% during a follow-up period of 1.5-38 months. Fifty percent of the tumors decreased in size or disappeared.Stereotactic radiation therapy (SRT) of brain metastases with high single doses was first given in 1975 at the Karolinska Hospital using a multi-cobalt-60 unit (gamma knife) (1). At present several thousand patients with intracranial metastases have been treated using this technique in different centers of the world ( 1-4). Local tumor control rate is around 90%. This SRT technique can frequently be used for treatment of inoperable tumors and those which are considered to be resistant to conventionally fractionated radiation. There is no other known treatment modality for solitary brain metastases which seems to

Quantifying isocenter measurements to establish clinically meaningful thresholds

“…This results in an ablative dose of radiation at the target with a steep dose gradient to minimize damage to tissues outside of the target 9 , 10 , 11 , 12 . SRS treatments are generally associated with small intracranial targets, and recently the term stereotactic body radiosurgery (SBRT) was developed to describe stereotactic‐guided radiotherapy to extracranial sites 13 , 14 , 15 , 16 , 17 …”

Imaged-guided liver stereotactic body radiotherapy using VMAT and real-time adaptive tumor gating. Concerns about technique and preliminary clinical results

“…[32][33][34][35][36] This was confirmed by Guckenberger M. et al who conducted a 4D-IGRT study in liver SBRT with acquisition of a CBCT study immediately before and after treatment delivery. Despite successful immobilization of the patient with a SBF, they observed considerable drifts in the target position independently from the bony anatomy in an order of 3.7 ± 2.2 mm on average.…”

Comparison of four techniques for spine stereotactic body radiotherapy: Dosimetric and efficiency analysis

“…Various techniques, including dose‐escalated radiotherapy, have been utilized to improve local control and symptom palliation 2, 3, 4, 5. Safe dose escalation using stereotactic body radiotherapy (SBRT) translates into durable pain relief, decompression of epidural extensions and local control rates of 70%–90% 6, 7, 8, 9, 10, 11, 12…”